Well drilling bit



June 20, 1967 M. E. WHITE WELL DRILLING BIT Filed July 22, 1965 FIG. 7.

FIG. 6.

FIG. 2.

MARVIN E. WHITE INVENTOR.

ATTORNEY United States Patent 3,326,308 WELL DRILLING BIT Marvin E.White, Fort Worth, Tex., assignor of fortynine percent to John G.Elstrand, Fort Worth, Tex. Filed July 22, 1965, Ser. No. 474,098 6Claims. (til. 175-413) This invention relates to a well drilling bit,and it concerns more particularly certain specific improvements in a bitas hereinafter described which has heretofore been employed for drillingcomparatively shallow, small diameter holes, commonly referred to asshot holes, for use in geophysical exploration operations in whichexplosive charges are placed in such holes and detonated from thesurface, and the resulting earth vibrations are recorded by seismograph.

The invention is applicable to a bit as described having a plurality ofthree circumferentially spaced removable blades which are received inlongitudinal slots therefor in thickened peripheral portions of atubular blade holder having an externally threaded shank portion forengagement with the lower end of a drill pipe. Each of the blades has ashort circumferentially extending portion extending laterally outwardlyfrom at least one side thereof, adjacent the upper end of the blade,which fits around the threaded shank portion of the blade holder andoverlies a discontinuous upwardly facing external shoulder on the bladeholder communicating with the upper ends of the longitudinal slotstherein. Said upper end portion of the blade is externally beveled forclamping engagement by a ring loosely surrounding the shank portion ofthe blade holder, in opposing relation to the lower end of the drillpipe and said shoulder, said ring being internally beveled on its underside, whereby a downward thrust is applied to the blades relative to theblade holder as the blade holder is advanced relative to the drill pipe,upon tightening the threads thereof, and the blades are rigidly andremovably clamped to the blade holder by abutting engagement of theirmutually opposing surfaces.

The invention contemplates certain improvements and refinements of themutually opposing surfaces on the blade holder and the blades,respectively, whereby the blades are clamped to the blade holder,between the blade holder and said ring, whereby the blades arepositively secured against displacement in any direction relative to theblade holder and the structure is additionally reinforced so that thebit is characterized by its ruggedness and dependability in use as wellas more efficient. The strength of the bit is comparable to that of thedrill pipe to which it is connected, and breakage of parts, as well ascostly fishing jobs to recover parts lost in the hole, are substantiallyavoided by use of the invention.

The invention also contemplates certain improvements in the cuttingsurfaces of the blades whereby the blades are less subject to wear andtheir useful life is increased,

while at the same time the rate at which the bit penetrates a formationbeing drilled is increased.

The invention will be readily understood by referring to the followingdescription and the accompanying drawing, in which:

FIG. 1 is a side elevational view of a well drilling bit embodying theinvention having two of its three blades removed to show details ofconstruction, showing one of the blades in place as seen from theleading side thereof relative to the direction of rotation of the bit,showing the heavy duty tubular blade holder having the longitudinalslots formed in thickened peripheral portions thereof for engagement bythe blades, showing the blade holder connected by its threaded shankportion to an adjoining section of drill pipe, shown fragmentarily, andshowing 3,325,398 Patented June 20, 1967 in longitudinal section thering surrounding said threaded shank portion of the blade holder, inopposing relation to the lower end of the drill pipe and a discontinuousupwardly facing external shoulder on the blade holder, and having ininternally beveled surface on its under side for clamping engagementwith the externally beveled, arcuate upper end portions of the severalblades, which extend circumferentially between said ring and saidshoulder, whereby a downward thrust is imparted to the blades relativeto the blade holder as the blade holder is advanced relative to thedrill pipe, upon tightening the threads thereof, and the blades arerigidly and removably connected to the blade holder, and are securedagainst displacement in any direction relative thereto, by abuttingengagement of their mutually opposing surfaces as hereinafter more fullydescribed;

FIG. 2 is a bottom plan view of the bit as illustrated in FIG. 1;

FIG. 3 is an elevational view showing one of the blades in its detachedposition as seen from the inner longitudinal edge thereof, facingradially outwardly relative to the assembled position of the blade;

FIG. 4 is an elevational view showing one of the blades in its detachedposition as seen from the outer longitudinal edge thereof, facingradially inwardly relative to the assembled position of the blade;

FIG. 5 is an elevational view showing one of the blades in its detachedposition as seen from the trailing side thereof relative to thedirection of rotation of the bit, in the assembled position of theblade;

FIG. 6 is a fragmentary sectional elevational view on an enlarged scaletaken on the line 6-6 of FIG. 2;

FIG. 7 is a fragmentary sectional elevational view on an enlarged scaletaken on the line 77 of FIG. 2; and

FIG. 8 is an inverted perspective view showing the ring illustrated inFIG. 1 as seen from the bottom and one side thereof.

Referring to FIGS. 1 and 2 of the drawing, the numeral 1 designatesgenerally a well drilling bit having the invention incorporated therein,and the numeral 2 indicates the lower end portion of a drill pipe, shownfragmentarily, having the bit 1 connected thereto.

The bit 1 includes a heavy duty tubular blade holder 3 which as shownhas a plurality of three longitudinal channels 4 formed in thickenedperipheral portions 5 thereof for engagement, respectively, by a likenumber of blades 6, and has an upwardly extending externally threadedshank portion 7 whereby the blade holder 3 is connected to the drillpipe 2.

The blade holder 3 has a discontinuous upwardly facing external shoulder8 communicating with the upper ends of the channels 4. A ring 9, whichloosely surrounds the threaded shank portion 7 of the blade holder 3, inopposing relation to the lower end of the drill pipe 2 and the shoulder8, is internally beveled on its under side, as at 10, for clampingengagement with the upper end portions 11 of the several blades 6, whichare externally beveled, as at 12, and extend circumferentially betweenthe ring 9 and the shoulder 8.

A downward thrust is imparted to the blades 6 relative to the bladeholder 3 by the action of the ring 9 as the blade holder 3 is advancedrelative to the drill pipe 2, upon tightening the threads thereof, andthe blades 6 are rigidly and removably clamped to the blade holder 3,between the blade holder 3 and the ring 9, by abutting engagement oftheir mutually opposing surfaces including the upwardly facing shoulder8 of the blade holder 3 and the opposing surfaces of the upper endportions 11 of the blades 6.

The blades 6 are secured in engagement with the channels 4 by abuttingengagement of the internally beveled surface on the under side of thering 9 with the externally beveled surfaces 12 on the upper end portions11 of the blades 6.

The blades 6 are generally planar and the outer long.- tudinal edgesthereof are straight for a major portion of their lengths, as at 13.Hard metal inserts, two of which are indicated by the numerals 14, 15,are applied to the leading sides of the blades 6, relative to thedirection of rotation of the bit 1, adjacent the outer longitudinaledges 13 thereof.

The lower end portions of the several blades 6, indicated by thenumerals 16, extend downwardly and radially inwardly toward each otherbelow the body of the blade holder 3, whereby they substantially meet,and the width of the blades 6 is progressively reduced by stepsimmediately adjacent the lower ends 16 thereof. Hard metal inserts, twoof which are indicated by the numerals 17, 18, are applied to theleading sides of the blades 6, relative to the direction of rotation ofthe bit 1, adjacent the lower ends 16 thereof.

The structure above described is conventional and is not claimed herein.This invention resides in the specific improvements hereinafterdescribed:

(1) The side walls of the channels 4 on the trailing sides of the blades6, relative to thedirection of rotation of the bit 1, are extendeddownwardly below the body of the blade holder 3, as at 19, FIG. 6, injuxtaposed relation to the lower end portions 16 of the blades 6, whichlikewise extend downwardly below the body of the blade holder 3 as abovedescribed, and in close proximity to the leading edges of the blades 6relative to the direction of movement of the bit 1 in a downwarddirection, whereby the lower end portions 16 of the blades 6 arereinforced against the torque to which they are subjected upon rotativemovement of the bit 1.

(2) The portions 19 of the side walls of the channels 4 on the trailingsides of the blades 6, relative to the direction of rotation of the bit1, which extend downwardly below the body of the blade holder 3 as abovedescribed, have downwardly and radially inwardly inclined abutments 20immediately above their lower ends terminating in downwardly extending,radially outwardly facing vertical abutments 21 immediately adjacenttheir lower ends, and the blades 6 have correspondingly shaped lugs 22on the trailing sides thereof, in opposing relation to the abutments 20,21, whereby the lower end portions 16 ofthe blades 6 are reinforcedagainst forces acting on them to squeeze them together.

(3) The side walls of the channels 4 on the leading sides of the blades6, relative to the direction of rotation of the bit 1, have cut outportions intermediate the ends of the channels 4 terminating in upwardlyand radially outwardly inclined abutments 24 spaced above the lower endof the body of the blade holder 3, and the blades 6 have correspondinglyshaped lugs 25 on the leading sides thereof, in opposing relation to theabutments 24, whereby the lower end portions 16 of the blades 6 arereinforced against forces acting on them to spread them apart.

(4) The side walls of the channels 4 on the trailing sides of the blades6, relative to the direction of rotation of the bit 1, have cut awayportions 26 beginning at their upper ends terminating in upwardly andradially outwardly inclined abutments 27 spaced below the shoulder 8,and the blades 6 have correspondingly shaped lugs 28 on the trailingsides thereof, in opposing relation to the abutments 27, whereby theblades 6 are secured against accidental displacement from the channels 4upon loosening the threads whereby the blade holder 3 is connected tothe drill pipe 2, to thereby disengage the ring 9 from its clampingengagement with the upper end portions 11 of the blades 6, upon changingthe blades 6.

(5 The extreme lower ends of the blades 6 are pointed and terminate inoppositely inclined, radially extending intersecting edges, andrectangular, substantially diamond shaped hard metal inserts 29, whichcorrespond to the inserts 17, 18, are applied to the leading sides ofthe blades 6, relative to the direction of rotation of the bit 1,adjacent the extreme lower ends of the blades 6, whereby the blades 6are more efficient from the standpoint of their rates of earthpenetration.

(6) Right angular hard metal inserts 30, which correspond to the inserts14, 15, are applied to the leading sides of the blades 6, relative tothe direction of rotation of the bit 1, and to the outer longitudinaledges 13 thereof, at the junctures of said outer longitudinal edges 13with the lower edges of the blades 6, whereby the blades 6 arecharacterized by their resistance to wear.

The invention may be modified in various ways without departing from thespirit and scope thereof.

I claim:

1. In a well drilling bit having replaceable blades, the combination ofa blade holder having a tubular body and having a plurality ofcircumferentially spaced longitudinal channels formed in thickenedperipheral portions thereof, and having an upwardly extending externallythreaded shank portion for engagement with a drill pipe whereby theblade holder is adapted to be connected to said pipe, the blade holderhaving a discontinuous upwardly facing external shoulder traversing theupper ends of said channels, below said shank portion, a plurality ofblades each received in one of said channels, said blades beingsubstantially planar and extending radially outwardly beyond saidchannels, the outer longitudinal edges of said blades being straight fora major portion of their lengths, the blades extending above and belowsaid channels and the lower end portions of the blades extendingdownwardly and radially inwardly toward each other below the body of theblade holder, whereby they substantially meet, the widths of the bladesbeing progressively reduced in the direction of their opposite endportions, respectively, and the upper end portions of the blades beingarcuate and extending laterally, circumferentially of the blade holder,above said upwardly facing shoulder, and being externally beveled, and aring loosely surrounding said shank portion, for abutting engagementwith the adjacent end of said pipe, said ring being internally beveledon its under side for abutting engagement with the externally beveled,arcuate upper end portions of the blades whereby the blades are adaptedto be clamped between the blade holder and said ring upon tightening thethreads whereby the blade holder is connected to said pipe, the sidewalls of said channels on the trailing sides of the blades, relative tothe direction of rotation of the bit, extending downwardly below thebody of the blade holder, in juxtaposed relation to the lower endportions of the blades, and in close proximity to the leading edges ofthe blades, relative to the direction of movement of the bit in adownward direction, whereby the lower end portions of the blades arereinforced against the torque to which they are subjected upon rotativemovement of the bit.

2. The structure of claim 1, the lower end portions of the side walls ofthe channels on the trailing sides of the blades, relative to thedirection of rotation of the bit, having downwardly and radiallyinwardly inclined abutments immediately above their lower endsterminating in downwardly extending, radially outwardly facing verticalabutments adjacent their extreme lower ends, and the blades havingcorrespondingly shaped lugs on the trailing sides thereof, in opposingrelation to said abutments, whereby the lower end portions of the bladesare reinforced against forces acting on them to squeeze them together.

3. The structure of claim 1, the side walls of said channels on theleading sides of the blades, relative to the direction of rotation ofthe bit, having cut out portions intermediate the ends of said channelsterminating in upwardly and radially outwardly inclined abutments spacedabove the lower end of said body, and the blades having correspondinglyshaped lugs on the leading sides thereof, in opposing relation to saidabutments, whereby the lower end portions of the blades are reinforcedagainst forces acting on them to spread them apart.

4. The structure of claim 1, the side walls of said channels on thetrailing sides of the blades, relative to the direction of rotation ofthe bit, having cut away portions beginning at their upper endsterminating in upwardly and radially outwardly inclined abutments spacedbelow said shoulder, and the blades having correspondingly shaped lugson the trailing sides thereof, in opposing relation to said lastmentioned abutments, whereby the blades are secured against accidentaldisplacement from said channels upon loosening the threads whereby theblade holder is adapted to be connected to said pipe, to therebydisengage said ring from its clamping engagement with the blades, uponchanging the blades.

5. The structure of claim 1, the extreme lower ends of the blades beingpointed and terminating in oppositely inclined, radially extendingintersecting edges, and the blades having rectangular, substantiallydiamond shaped hard metal inserts applied to the leading sides thereof,relative to the direction of rotation of the bit, adjacent their extremelower ends, whereby the blades are characterized by their efliciencyfrom the standpoint of their rates of earth penetration.

References Cited UNITED STATES PATENTS 2,498,251 2/1950 Creel 175-4122,615,684 10/1952 Hawthorne 175-412 2,978,049 4/1961 Skidmore 175-413 X3,075,594 l/1963 Creel 175-412 3,099,325 7/1963 Purser 175-412 3,132,7085/1964 Stockard 175-412 CHARLES E. OCONNELL, Primary Examiner.

20 N. C. BYERS, Assistant Examiner.

1. IN A WELL DRILLING BIT HAVING REPLACEABLE BLADES, THE COMBINATION OFA BLADE HOLDER HAVING A TUBULAR BODY AND HAVING A PLURALITY OFCIRCUMFERENTIALLY SPACED LONGITUDINAL CHANNELS FORMED IN THICKENEDPERIPHERAL PORTIONS THEREOF, AND HAVING AN UPWARDLY EXTENDING EXTERNALLYTHREADED SHANK PORTION FOR ENGAGEMENT WITH A DRILL PIPE WHEREBY THEBLADE HOLDER IS ADAPTED TO BE CONNECTED TO SAID PIPE, THE BLADE HOLDERHAVING A DISCONTINUOUS UPWARDLY FACING EXTERNAL SHOULDER TRAVERSING THEUPPER ENDS OF SAID CHANNELS, BELOW SAID SHANK PORTION, A PLURALITY OFBLADES EACH RECEIVED IN ONE OF SAID CHANNELS, SAID BLADES BEINGSUBSTANTIALLY PLANAR AND EXTENDING RADIALLY OUTWARDLY BEYOND SAIDCHANNELS, THE OUTER LONGITUDINAL EDGES OF SAID BLADES BEING STRAIGHT FORA MAJOR PORTION OF THEIR LENGTHS, THE BLADES EXTENDING ABOVE AND BELOWSAID CHANNELS AND THE LOWER END PORTIONS OF THE BLADES EXTENDINGDOWNWARDLY AND RADIALLY INWARDLY TOWARD EACH OTHER BELOW THE BODY OF THEBLADE HOLDER, WHEREBY THEY SUBSTANTIALLY MEET, THE WIDTHS OF THE BLADESBEING PROGRESSIVELY REDUCED IN THE DIRECTION OF THEIR OPPOSITE ENDPORTIONS, RESPECTIVELY, AND THE UPPER END PORTIONS OF THE BLADES BEINGARCUATE AND EXTENDING LATERALLY, CIRCUMFERENTIALLY OF THE BLADE HOLDER,ABOVE SAID UPWARDLY FACING SHOULDER, AND BEING EXTERNALLY BEVELED, AND ARING LOOSELY SURROUNDING SAID SHANK PORTION, FOR ABUTTING ENGAGEMENTWITH THE ADJACENT END OF SAID PIPE, SAID RING BEING INTERNALLY BEVELEDON ITS UNDER SIDE FOR ABUTTING ENGAGEMENT WITH THE EXTERNALLY BEVELED,ARCUATE UPPER END PORTIONS OF THE BLADES WHEREBY THE BLADES ARE ADAPTEDTO BE CLAMPED BETWEEN THE BLADE HOLDER AND SAID RING UPON TIGHTENING THETHREADS WHEREBY THE BLADE HOLDER IS CONNECTED TO SAID PIPE, THE SIDEWALLS OF SAID CHANNELS ON THE TRAILING SIDES OF THE BLADES, RELATIVE TOTHE DIRECTION OF ROTATION OF THE BIT, EXTENDING DOWNWARDLY BELOW THEBODY OF THE BLADE HOLDER, IN JUXTAPOSED RELATION TO THE LOWER ENDPORTIONS OF THE BLADES, AND IN CLOSE PROXIMITY TO THE LEADING EDGES OFTHE BLADES, RELATIVE TO THE DIRECTION OF MOVEMENT OF THE BIT IN ADOWNWARD DIRECTION, WHEREBY THE LOWER END PORTIONS OF THE BLADES AREREINFORCED AGAINST THE TORQUE TO WHICH THEY ARE SUBJECTED UPON ROTATIVEMOVEMENT OF THE BIT.